Recently, NAND flash devices have become very popular with respect to their use in mobile applications and mobile storage applications such as flash cards, digital audio/video players, cell phones, USB flash drives and solid state drives (SSDs) for hard disk drive (HDD) replacement. With an increase in the density requirement in the market, NAND flash provides high density with low cost.
NAND flash memories are described in, for example,                Kenichi Imamiya, et al., “A 125-mm2 1-Gb NAND Flash Memory With 10-MByte/s Program Speed,” IEEE J Solid-State Circuits, vol. 37, no. 11, pp. 1493-1500, November 2002;        June Lee et al., “A 90-nm CMOS 1.8-V 2-Gb NAND Flash Memory for Mass Storage Applications,” IEEE J Solid-State Circuits, vol. 38, no. 11, pp. 1934-1942, November 2003;        Ken Takeuchi, et al., “A 56 nm CMOS 99 mm2 8 Gb Multi-level NAND Flash Memory with 10 MB/s Program Throughput,” ISSCC Dig. Tech. Paper, pp. 144-145, February 2006.        